Screw jack



R. c. FlNcH SCREW JACK oct. 30, 192,3.

Filed June 7. 1921 fr 1 A la ffffffff ,ff-A

SLW@ gl/ f Hbc/7 RAY c. Fnvcn, or eremita, WASHINGTON.

SCREW reen.

Application led June t,

To all whom. z't may concern.'

Be it known that I, RAY C. FINCH, a. citizen of the United States, residing at Spokane, in Spokane County and State of Washington, have invented certain new and useful Improvements in Screw Jacks, of which the following is a specification.

My present invention relates to unprovemcnts in screw jacks which, while designed especially for use in connection with automobiles or other vehicles is capable of many other uses in lifting or elevating comparatively heavy bodies.

he primary object of my invention is the provision of a jack that is compact in its arrangement, permitting its insertion or placement in small space or area, and which may be operated with facility and extended quickly to lift or elevate a load. By the utilization of a minimum number of parts I am enabled to rovide a strong and durable device of this cliaracter not likely to become disarranged or broken. With the above ends in view the invention consists in certain novelcombinations and arrangements of arts as will be hereinafter more specifical y pointed outand claimed.

In theacompanying drawings I have illustrated one complete example of the physical embodiment of :my invention in which the parts are combined and arran according to the best mode I have thus far fi devised for the practical application of the principles of my invention.

Figure l is a view in side elevation of a jack embodying my invention showing the telescopic handle bar which is horizontall reciprocable for operating the screws.

Figure 2 is a somewhat enlarged view in elevation and partly in section at line 2 2 of Figure 3 disclosing the' interior of the jack, the telescoping and the retaining means for the non-rotatable screw bar, and connections.

Figure 3 is a top plan view of the pack.

Figure 4 is an enlarged, horizontal sectional view at line 4-4 of Figure 1 showing the bearing head of the handle bar and the pawl and ratchet mechanism of the screw bars.

Figure 5 is an enlarged detail view partly in section showing the inner, non-rotatable tubular screw bar and its retaining means.

In the preferred form of the invention as shown inthe drawings l utilize a comparatively wide, circular base plate l for the supscrew bars or screws th rsa1. serial un. 475,324.

port of thejack, from which base rises the pedestal or barrel 2 having an interior chamber or bore 3 which may be supplied with oil as a lubricant for the operating parts of the screw jack.

At its upper end the pedestal is fashioned with an internally screw threaded head 4, of less diameter than the cylindrical chamber 3, and rising from the base 1 within the chamber 3 is a stem 5. This stem is located centrally of the hollow pedestal and integral or rigid with its base, and is rectangular or square in cross section, its upper end terminating a slight distance above the pedestal.

Within the threaded head 4 of the pedestal is a rotatable, traveling, tubular screw bar 6 provided with both internal and eX- ternal screw threads and provided with open bottom and top ends, th tubular screw bar however 1s fashioned with a cylindrical bearing head 7 having a smooth top face and lateral ratchet teeth 7 extending around its periphery. This bearing head or ratchet head of the tubular screw is engaged by a spring pressed pawl 8 to revolve the tubular screw, and the ratchet head is encased by the handle head 9 cylindrical in formation and fashioned with a laterally extending socket sleeve 10 in which the tubular handle bar 11 is inserted. By means of a ned lpin 12 `in the handle bar 11 and a yonet slot 13 in the socket sleeve the handle bar may be quickly attached to the socket sleeve for operating the jack, or detached therefrom when the jack is not in use.

The pawl 8 as seen in Figure 4 the external teeth 7 of the ratchet the tubular screw bar open end of the handle bar 11 by means of e tangentially disposed pin 14 in the: handle bar which passes transversely across the groove 15 in the pawl. This pin prevents rotation ofthe pawl and also serves to limit its outward movement from the handle bar. The pawl is held to its work by means of the coiled spring 16 within the handle bar located between the pawl and a washer 17, the latter being retained by means of the pin 12 fixed in the handle bar. performs its usual function in co-action with ratchet head as the handle bar is osengages head on the cillated horizontally or turned around the ack, to project the outer, rotatable screw ,ar d from the pedesta. The leverage of e upper end of this' and is retained in the i bar,

the handle bar may be increased by utilizing the extension section 18 which is a telescopic tube fitting over the bar section 11, and the extension section is slotted at 19 to eo-act with a guide pin 2() in the section 11.

When space vdoes not permit the use of this extension section it may be closed over the stationary section 11 to shorten the handle bar and consequently the leverage thereof.

1Within the outer tubular, threaded, screw is located a non-rotatable, inner, tubular screw bar 21 having exterior threads in engagement with the interior threads of the outer bar with which bar the inner bar telescopes, and from which it may be projected by action of the head -7 and the full length of' interior threads of the outer tubular bar. At its lower end this inner tubular screw has an open center 22, and at its upper end is provided a swiveled supporting head 23 rotatable in-the boss 24 of the inner screw bar.

The tubular inner screw bar is fashioned with a squared bore 25, in the four faces of which are provided longitudinally extending grooves 26, and withinthe inner screw bar and supported on the stem 5 is a slide tube 27 having a head 28 with 4lateral lugs 29 traveling in the respective grooves 26 of the inner screw bar. y

In operating the tool, assuming a load to be supported on the swivel`head 23, the handle bar 11-18 may be oscillated, or turned, horizontally, and through the pawl and ratchet connection the outer tubular screw bar is turned in the threaded head 4, thus elevating this bar and bodily carrying Vith it the non-rotatable inner tubular screw Because of the inner screw bar,

the non-rotary condition of the latter, through the screw threads between the outer tubular bar and the. inner tubular bar, is projected from the outer bar, and is held from turning by the slidable sleeve 27 on its stem 5, which sleeve through its lugs 29 guides the movement of the inner bar. When the inner bar has been elevated sufficiently for the lower closed end 22 thereof to encounter the lugs 29 of the sleeve, the latter is lifted on its stem and continues to guide and prevent turning of the inner tube.

After the load has been -l'ifted as 4desired the screw bars may be retracted by first shifting or reversing the pawl 8, and this may be accomplished by giving the'handle bar 11 a half turn in the socket sleeve 10, whereupon the working stroke of the pawl will bek in the opposite direction from the former movement, and the two screw bars may be turned home. lVhen not in use the handle bar may be bodily detached by withdrawing the pin 12 through the bayonet slot 13 as seen in Figure 3.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is The combination with a hollow vpedestal having an integral central square stein and a threaded bearing head, of an interiorly and exteriorly threaded,v tubular screwfbar in said head and means for turning said bar, a second tubular screw bar within the first bar havingl an openin in its lower vend and provided with interlor, longitudinal grooves, a. .telescoping sleeve on said stem, a square closed head on said sleeve, and lugs on said square head engaging said grooves.

In testimony whereof I affixl my signature.

RAY C. FINGH. 

